Constantly tired - blood tests normal

For the last 7 years or so I’ve always felt I needed more sleep than average. Last year, I realised it was really affecting my life to the point where I couldn’t concentrate on work in the afternoon, cancelled or avoided making plans on days off as I’d much rather sleep for a couple of hours in the afternoon. I just feel I have no energy all the time.

We did blood tests last year and I had a vitamin D deficiency. I got some high dosage tablets and then have been on 4000 IU Vitamin D Tablets since. It made such a difference and I didn’t nap for several weeks in a row.

In the last couple of months my symptoms have come back. I went back for bloods but they’ve come back normal. I don’t know what the problem is or what this could be but I am at my wits end. It’s really affecting my life. I avoid taking the dog out at lunch as I’d much rather sleep, so my husband does it instead. I don’t stay long at events. I don’t make plans.

Has anyone else experienced this and found the problem?

I am 31F and have no other illnesses. I have depression on and off but at the moment I don’t feel depressed and have been off anti depressants for at least half a year now.

Thank you